Masato Jin is an eccentric genius engineer who prefers minor flaws to perfection. Though working in another block during the incident thirteen years ago, Masato ended up in subspace regardless when his fellow researchers sacrificed themselves to trap Messiah. He is known for his utter disregard for rules and authority (one of his first actions as Beet Buster being to steal mass amounts of Enetron) and acting on his own. He often addressing Commander Kuroki by an embarrassing nickname. Stuck in subspace, Masato created Beet J. Stag to aid him when he sends an avatar of himself to reality, as he is unable to transfer his true body. The use of an avatar explains why he looks the same age as he was thirteen years ago. Along with the creation of J, Masato also created his and J's unique Buster Gears, enabling him to transform and fight as the gold-colored Beet Buster. Despite his seemingly immature facade, he is truly quite wise, seen when he tells Ryuji that he would not be able to do much if he only watched over and fought for others, thus prompting him to search for a personal reason to fight so that he could do so effectively. Masato often flashes the sign of the horns with the back of his hand out, resembling the horn of a Japanese rhinoceros beetle. As an avatar whose existence in the real world is entirely dependent on J, he can't transform on his own and requires J's Marker System to activate their Buster Machines. While his body in the real world is an avatar and thus incapable of dying, having this avatar body destroyed and recreated puts a serious strain on Masato's true body.